Met 13 - Aviation Weather Reports

What is the purpose of meteorology knowledge for pilots?

To recognize and avoid hazardous weather using available information

What does SARPS Annex 3 define?

Standards for aviation weather reporting and forecasting

What is the role of the WMO?

To implement SARPS Annex 3 standards globally

What does WAFS provide?

Upper air forecasts

What are the two WAFCs?

NOAA (US) and UK Met Office

What do WAFCs forecast?

Upper winds, temperature, humidity, CB areas, icing, turbulence

What is a weather report?

A factual statement of actual weather at a place and time

What is a weather forecast?

A prediction of expected weather over a period

What report gives actual weather conditions?

METAR

What is a SPECI?

A special weather report triggered by specific criteria

What is a radiosonde?

A balloon-borne instrument that transmits upper-air weather data

What measurements does a radiosonde provide?

Altitude, pressure, temperature, humidity, wind speed and direction

What are the two satellite image types?

Visible and infrared (IR)

What is a visible satellite image?

A black-and-white photo-like image from space

What are the limitations of visible satellite images?

Not available at night, snow can look like cloud

What is an infrared satellite image?

An image based on temperature differences

What is a limitation of IR images?

High clouds can hide lower layers, fog may look like surface

Why are satellite images processed?

To add grid lines, coastlines, and daylight adjustments

What does weather radar detect?

Precipitation areas and thunderstorm activity

What are AIREPs?

Pilot weather reports

When is an AIREP SPECIAL required in Europe?

When severe icing, turbulence, CB, or other hazards are encountered

What should PPL pilots report when encountered?

Windshear

Who produces METARs?

A Meteorological Watch Office (MWO)

How often are METARs issued in the UK?

Every 30 or 60 minutes

What does the location in a METAR use?

Four-letter ICAO code

How is METAR time coded?

Day of month + UTC time + 'Z'

What does 'AUTO' mean in a METAR?

Automated report with no human input

How is wind reported in a METAR?

Direction in degrees True and speed in knots

What does 'VRB' in wind mean?

Variable wind direction

What indicates a calm wind?

'00000' followed by units

What is reported if wind varies by 60° or more?

Direction variation

How is visibility reported in METARs?

Prevailing and minimum vis in meters or kilometers

What does '9999' mean in a METAR?

Visibility 10 km or more

What does '0000' mean in a METAR?

Visibility less than 50 m

What is RVR?

Runway Visual Range, given in meters for the touchdown zone

When is RVR reported?

When visibility or RVR is below 1500 m

How is cloud coverage coded?

FEW, SCT, BKN, OVC with cloud base in hundreds of feet

What does CB or TCU mean in METARs?

Cumulonimbus or towering cumulus cloud

What does 'NSC' mean?

No significant cloud below 5000 ft and no CB or TCU

What does 'VV///' mean?

Vertical visibility cannot be assessed

What does 'CAVOK' stand for?

Ceiling and visibility OK (10 km+, no significant cloud or weather)

What is QNH in a METAR?

Sea-level pressure in millibars, starting with 'Q'

What does 'A' prefix indicate for QNH?

Pressure in inches of mercury

What is 'RE' in a METAR?

Recent weather since last observation

What does 'BECMG' in a trend mean?

Becoming

What does 'TEMPO' in a trend mean?

Temporary

Where is 'AUTO' placed in a METAR?

After the date/time group

What does 'NDV' mean in a METAR?

No directional variation in visibility reported

What does 'UP' mean in a METAR?

Unidentified precipitation

What does 'FZUP' mean?

Freezing unidentified precipitation

What does 'NCD' mean?

No cloud detected below 5000 ft

What does 'REUP' mean?

Recent unidentified precipitation

What does '////' in visibility mean?

Visibility sensor failure

What does '/////////' in cloud group mean?

Cloud sensor failure

What is VOLMET?

A recorded broadcast of METARs for selected airports

What does VOLMET help pilots do?

Stay updated on en route weather conditions

What is ATIS?

Automatic Terminal Information Service

What info does ATIS broadcast?

METAR and other arrival/departure info for an airfield

Where is ATIS broadcasted?

On VHF or nearby VOR frequency

When should a pilot check ATIS?

Before arrival or departure at an airfield